Yes, cold water is Milton. You can just use any old Tupperware box with a lid, chuck in liquid/half a tablet fill with cold water and then you can just submerge stuff as required for 15 minutes then its ready to go.
Personally I bought an electric steriliser because I liked being able to just switch it on/off once a day and forget about rather than remembering to change water etc. I got mine for £10 on our local Facebook selling page.
You'll be fine, I bottle fed my first because I didn't really know anything about breastfeeding (ridiculous I know but my family were/are set against it and had no friends who breastfed either) and you soon get into a routine.
You can either make each bottle fresh as you go by putting in 3/4 boiling water, adding recommended powder, shake then add last 1/4 cooled boiled water, shake again and you're ready to go.
Or you can make in advance.
Sterilise your bottles, fill each one with correct amount of boiling water, add recommended powder, shake, cool in basin of cold water for 15 minutes and put in back of fridge for up to 24 hours.
I found the second method easier as it meant I could prep the next days feed at bedtime and that was it sorted.
I breastfed my second for 16 months and tried lots of different bottles but NUK was the only one that she would take, MAM are supposed to be good for mix feeding but I think it is trial and error.
I found the Avent manual and hand expressing much better than the electric pumps I tried (Spectra 3, Medela Mini and Tommee Tippee) but I never managed more than 4oz at once.